I updated WAMP to version 3.2.6, even installed Aestan version 3.2.4.2 separately (though the installer told me it was installed already). No errors when I start WAMP with a PHP version other than 8.1 but I do get [EParseError] Unrecognized parameter name "Type" on line 592 when starting Wampmanager using PHP 8.1. The services are started and phpinfo() tells me I am actually using PHP version 8.1.
PHP version 8 was installed using the WAMP installation utility.
Solved by (also) updating Apache to version 2.4.51